I am using Microsoft Publisher 2007 SP1 on a Windows XP Pro 2002 SP3 box. When I go File > Publish as PDF or XPS and publish a document using the default settings for high quality printing with the "Open file after publishing" option enabled, the PDF opens in Adobe Acrobat 4.0. In the Windows Tools > Folder Options > File Types window, I have configured the file type PDF to open with Adobe Reader 9.0. When I double click a PDF on the desktop, the PDF opens in Adobe Reader 9.0. When I use the Microsoft Publisher "publish as PDF or XPS" plug-in to create a PDF, the PDF opens in Adobe Acrobat 4.0. Why?